Unit or grid.



E. O. VAN GLAHN.

UNIT R GRID. APPLICATION FILED SEPT. 19,1913.

Patented Feb. 24, 1914.

UNITED STATES PATENT OFFICE.

EDWARD C. VAN GLAHN, OF NEW YORK, N. Y., ASSIGNOR TO NATIONAL ELECTRIC UTILITIES CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

UNIT 03 GRID.

Specification of Letters Patent.

Patented Feb. 24, 1914.

To all whom it may concern:

Be it known that I, EDWARD G. VAN GLAHN, a citizen of the United States, residing at the city of New York, in the county and State of'New York, have invented new and useful Improvements in Units or Grids, of which the following is a specification.

This invention relates to heating units or grids for use in electric ranges, ovens and similar cooking and heating devices, and it comprises simple and efficient means for supporting the heatin element, whereby the usual numerous insu ators heretofore employed may be dispensed with and whereby the supporting means may be removed to substitute new ones without the necessity of removing the heating element.

Electric grids, particularly for large fur-- naces and ovens, must be of especially strong construction to provide against melting and warping due to the intense heat to which they are subjected. The frame and radiating surface must be thoroughly electrically insulated from the heating element, which is usually in the form of coiled wire. In heretofore known electric grids, so far as I an aware, the heating element is usually supported from a large number of binding posts secured in a plate carried by the frame. Frequently more than one hundred such posts are necessary for a grid 25x17 inches, and each such post'mu'st be insulated from the plate. Usually mica disks or other form of insulation is employed, but, because of the construction, the posts frequently become grounded or short-circuited, and it is then necessary to substitute a new one. To do this in such heretofore known grids, the element wire must be completely unstrung and new posts secured in place on the plate and the element wire restrung to position through all the posts or supports. This involves considerable loss of time and is an expensive method of repairing. Furthermore, because of the construction, there is a great tendency for the grids to warp.

The present invention has for its objects the production of a heating unit or grid which obviates the disadvantages of the heretofore known grids and which is very strong and durable and comparatively inexpensive in construction.

vAnother object of the invention is the provision of a grid having relatively few number of parts and being as light in weight as is consistent with the requisite strength.

lVhile it has the advantage of being of the radiant heat type, fully exposedto the air on both sides, it can be completely inclosed by the use of baflle irons or other sheet metal covering and by the use of any mate rial to reflect heat its efiiciency may be correspondingly increased.

The invention comprises, a frame made preferably of angle iron with a plurality of transverse supports, preferably of T-iron construction or bars having flanges, and arranged in such manner as to provide for expansion and contraction of the metal, and having means such as seats for the reception and retention of insulating element supports preferably in the form of bushings of porcelain, electrobestos, lava or other insulating material. The heating element of carbon or in the form of coiled wire is threaded through the bushings and suitably connected to different terminals whereby it may be used to furnish several diiferent heats. Specifically the supporting irons are made in complementary halves and are arranged to be removably secured to the frame; and specifically the insulators are made of two complementary sections in order that they maybe inserted in place around the element wire without the necessity of stringing or threading the wire through them. This construction is very advantageous if for any reason it is desired to repair the grid, for instance, by replacing an ac-.

cidentally broken insulating bushing. By this construction the heating element is completely exposed allowing thorough circulation and all danger of grounding or shortcircuiting is completely eliminated; whereas, in the old type of heretofore referred to, the heating element is not exposed, because it is inclosed by the sup orting plate for the posts and, because of tie con struction and number of posts used, the liability for short-circuiting is very great. The loose connection of the bars to the grid frame and the loose engagement of the thimbles in their seats constitute important parts of my'invention, as the former arrangement prevents warping and buckling of the frame and the latter arrangement prevents breakage of the thimbles due to unequal expan- S1011.

one form of a speci c embodiment of my invention and in the several views of which similar reference characters designate corresponding parts, Figure 1 is a top plan view of a complete grid Fig.2 isa transverse section along line 2-2 of Fig. 1 on an enlarged scale; Fig. 3 is a view similar to Fig. 2, showin the upper T-iron separated and without the element supports; Fig. etis an enlarged longitudinal section along line 4:-4: of Fig. 1; Fig. 5 is a detailed perspective of one form of bushing or thimble; and Fig- 6 is a transverse section through another form of thimble'which is advantageous when repairing the grid.

In the form of invention here shown, for the sake of exposition, 1 indicates a frame preferably of angle iron having along one longitudinal side 2 the spaced slots 3, corresponding in number to the number of sup ports or bars for thebushings. The opposite longitudinal side 4 of the frame is provided with the same number of spaced slots 5 for the bushing supports. These supports 6 are bent at one end with the right-angle portion 7, which is' arranged to be inserted in the slots 5, when the support may then be brought parallel with the frame, whereupon the flange 8 on the opposite extremity is inserted in the slot 3 and a cotter-pin 9 passed through the hole in the flange to re tain the support in position. ihe under side of the frame is provided with a corresponding number of T-irons 10, either permanently or removably secured in the frame by means of the slots and tongues 11.

The upper and lower thimble supports are provided with complementary recessed portions 12, corresponding to the contour of the bushings to be employed and forming seats for them. When the apparatus is first constructed, the bushings are preferably integral and are placed in the seats 12 and located in position by the upper supports 6 and their seats and the element wire is then threaded through them; but when it is desirable to replace a bushing for any reason, those shown in Figs. 5 and 6 may be employed.

13 designates a solid bushing used when the apparatus is first assembled.

14 designates one form of a split bushing or thimble, and 15 designates a still difierent form.- The thimble 15 is provided'with a tongue and groove 16 to prevent lateral displacement of the complementary halves.

The arrangement of heating element 17 having the two terminals 18 and 19 and bus bar 20 is not a part of my invention, except in combination with the improved insulator supports which adapt it for advanta In the accompan ing drawings showing use in a grid, and I do not claim such arrangement herein.

Because of the tendency of the apparatus ofthe present to warp in use and to expand, provision is made to prevent such warping and expansion having deleterious influence upon the bushings. The supports for. the bushings are preferably arranged to loosely engage them and to leave room for the unequal expansion and contraction of the metal of the bars and of the porcelain, electroasbestos, lava or other material of the bushings.

I do not limit my invention to the exact construction shown, as many different forms embodying the invention may be availed of. I consider myself entitled to the general construction and arrangement of parts as shown without limitation to the specific arrangement and construction and the use of particular material.

What I claim is 1. A11 electric grid comprising a main support, a plurality of sets of spaced transverse supports carried by the main support, each set' comprising complementary halves having insulator seats therein, insulators in said seats, at least one half of each of saidsets being independently removable from its associated half whereby the insulators of one set of supports may be accessible without disassembling the other supports, and a heating element carried by said insulators.

2. A grid comprising a frame having a series of spaced slots on opposite sides, a plurality of lower cross-bars having seats for insulators, a plurality of upper crossbars having insulator seats corresponding to the insulator seats of the lower bars and having at opposite ends, means for engagement with the slots of the said sides, insu-- lators maintained in said seats by said crossbars, and a heating elementsupported in the frame by said insulators.

3. An electric grid comprising a frame having means on opposite sides for maintaining insulator retaining means in posi tion, a plurality of lower transverse insulator supports carried by said frame, a pinrality of upper insulator retaining means having opposite ends adapted for engagement with the means of said frame, a p'lurality of independent insulators removably secured in the frame through said insulator retaining means and said supports, and a heating element supported in said. frame by said insulators.

An electric grid comprising a frame, a plurality of lower T cross-bars having insulator'seats therein, a plurality of upper cross-bars having insulator seats therein, plurality of insulators, each located between said bars and in seats, and a heating element supported by said insu 1,oaa,114

sulator retaining means carried by saidframe and secured by the means on the frame, insulators carrledby said retaining means, and a heating element carried by said insulators, at least one set of said insulator retaining means being arranged so that it may be removed.

' 7. In a grid, a frame of angle iron, a set of transverse bars secured to the vertical side of said angle iron, and having means for maintaining insulators in place, another set of transverse bars secured to thehorizontal sides of said angle iron and having means for retaining insulators in place, insulators in said means, and a heatin element supported in said frame by said insulators.

8. An electric grid comprising a frame, cross-bars having flanges with seats therein, individual insulators in. said seats, and a heating element supported by said bars through said insulators.

9. electric grid comprising a frame, a plurality of lower cross-bars having upwardly projecting flanges with insulator seats therein, a plurality of corresponding upper bars having downwardly projecting flanges with insulator seats therein, a plurality of insulators each located between said flanges and in said seats, and a heating element supportedby said insulators.

10. An electric grid comprising a rigid frame of-a'ngle-iron, members secured thereto at opposite ends for supporting insulators, hollow insulators carried by said members, and a heating element carried by said insulators. v

11. An electric grid comprising a rigid angle-iron frame, element supports loosely connected thereto, -a heating element supported by said supports, and insulators for said heating element.

' 12. In an electric grid, supports for a heating element and insulators carried by said supports, said insulators "comprising split thimbles having interlocking portions. In testimony whereof, I have hereunto set my hand in the presence of witnesses.

EDWARD C. VAN GLAHN.

Witnesses:

M. W. RICE Annual) M. Ii-IoUon'roN. 

